/*******************************************************************************
* Copyright (c) 2005, 2017 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
*******************************************************************************/
package org.eclipse.dltk.tcl.internal.ui.text;
import java.util.Arrays;
import org.eclipse.core.runtime.Assert;
import org.eclipse.dltk.tcl.ui.text.TclPartitions;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.ITypedRegion;
import org.eclipse.jface.text.Region;
import org.eclipse.jface.text.TextUtilities;
import org.eclipse.jface.text.TypedRegion;
public class TclDocumentScanner {
/**
* Returned by all methods when the requested position could not be found,
* or if a {@link BadLocationException} was thrown while scanning.
*/
public static final int NOT_FOUND = -1;
/**
* Special bound parameter that means either -1 (backward scanning) or
* <code>fDocument.getLength()</code> (forward scanning).
*/
public static final int UNBOUND = -2;
/**
* Specifies the stop condition, upon which the <code>scanXXX</code> methods
* will decide whether to keep scanning or not. This interface may
* implemented by clients.
*/
private static abstract class StopCondition {
/**
* Instructs the scanner to return the current position.
*
* @param ch
* the char at the current position
* @param position
* the current position
* @param forward
* the iteration direction
* @return <code>true</code> if the stop condition is met.
*/
public abstract boolean stop(char ch, int position, boolean forward);
/**
* Asks the condition to return the next position to query. The default
* is to return the next/previous position.
*
* @return the next position to scan
*/
public int nextPosition(int position, boolean forward) {
return forward ? position + 1 : position - 1;
}
}
/**
* Stops upon a non-whitespace (as defined by
* {@link Character#isWhitespace(char)}) character.
*/
private static class NonWhitespace extends StopCondition {
@Override
public boolean stop(char ch, int position, boolean forward) {
return !Character.isWhitespace(ch);
}
}
/**
* Stops upon a non-whitespace character in the default partition.
*
* @see NonWhitespace
*/
private final class NonWhitespaceDefaultPartition extends NonWhitespace {
@Override
public boolean stop(char ch, int position, boolean forward) {
return super.stop(ch, position, true)
&& isDefaultPartition(position);
}
@Override
public int nextPosition(int position, boolean forward) {
ITypedRegion partition = getPartition(position);
if (fPartition.equals(partition.getType()))
return super.nextPosition(position, forward);
if (forward) {
int end = partition.getOffset() + partition.getLength();
if (position < end)
return end;
} else {
int offset = partition.getOffset();
if (position > offset)
return offset - 1;
}
return super.nextPosition(position, forward);
}
}
/**
* Stops upon a character in the default partition that matches the given
* character list.
*/
private final class CharacterMatch extends StopCondition {
private final char[] fChars;
/**
* Creates a new instance.
*
* @param ch
* the single character to match
*/
public CharacterMatch(char ch) {
this(new char[] { ch });
}
/**
* Creates a new instance.
*
* @param chars
* the chars to match.
*/
public CharacterMatch(char[] chars) {
Assert.isNotNull(chars);
Assert.isTrue(chars.length > 0);
fChars = chars;
Arrays.sort(chars);
}
@Override
public boolean stop(char ch, int position, boolean forward) {
return Arrays.binarySearch(fChars, ch) >= 0
&& isDefaultPartition(position);
}
@Override
public int nextPosition(int position, boolean forward) {
ITypedRegion partition = getPartition(position);
if (fPartition.equals(partition.getType()))
return super.nextPosition(position, forward);
if (forward) {
int end = partition.getOffset() + partition.getLength();
if (position < end)
return end;
} else {
int offset = partition.getOffset();
if (position > offset)
return offset - 1;
}
return super.nextPosition(position, forward);
}
}
/** The document being scanned. */
private final IDocument fDocument;
/** The partitioning being used for scanning. */
private final String fPartitioning;
/** The partition to scan in. */
private final String fPartition;
/* internal scan state */
/** the most recently read character. */
private char fChar;
/** the most recently read position. */
private int fPos;
/**
* The most recently used partition.
*
*
*/
private ITypedRegion fCachedPartition = new TypedRegion(-1, 0,
"__no_partition_at_all"); //$NON-NLS-1$
/* preset stop conditions */
private final StopCondition fNonWSDefaultPart = new NonWhitespaceDefaultPartition();
private final static StopCondition fNonWS = new NonWhitespace();
/**
* Creates a new instance.
*
* @param document
* the document to scan
* @param partitioning
* the partitioning to use for scanning
* @param partition
* the partition to scan in
*/
public TclDocumentScanner(IDocument document, String partitioning,
String partition) {
Assert.isLegal(document != null);
Assert.isLegal(partitioning != null);
Assert.isLegal(partition != null);
fDocument = document;
fPartitioning = partitioning;
fPartition = partition;
}
/**
* Calls
* <code>this(document, IDocument, IDocument.DEFAULT_CONTENT_TYPE)</code>.
*
* @param document
* the document to scan.
*/
public TclDocumentScanner(IDocument document) {
this(document, TclPartitions.TCL_PARTITIONING,
IDocument.DEFAULT_CONTENT_TYPE);
}
/**
* Returns the position of the closing peer character (forward search). Any
* scopes introduced by opening peers are skipped. All peers accounted for
* must reside in the default partition.
*
* <p>
* Note that <code>start</code> must not point to the opening peer, but to
* the first character being searched.
* </p>
*
* @param start
* the start position
* @param openingPeer
* the opening peer character (e.g. '{')
* @param closingPeer
* the closing peer character (e.g. '}')
* @return the matching peer character position, or <code>NOT_FOUND</code>
*/
public int findClosingPeer(int start, final char openingPeer,
final char closingPeer) {
Assert.isLegal(start >= 0);
try {
int depth = 1;
start -= 1;
while (true) {
start = scanForward(start + 1, UNBOUND, new CharacterMatch(
new char[] { openingPeer, closingPeer }));
if (start == NOT_FOUND)
return NOT_FOUND;
if (fDocument.getChar(start) == openingPeer)
depth++;
else
depth--;
if (depth == 0)
return start;
}
} catch (BadLocationException e) {
return NOT_FOUND;
}
}
/**
* Returns the position of the opening peer character (backward search). Any
* scopes introduced by closing peers are skipped. All peers accounted for
* must reside in the default partition.
*
* <p>
* Note that <code>start</code> must not point to the closing peer, but to
* the first character being searched.
* </p>
*
* @param start
* the start position
* @param openingPeer
* the opening peer character (e.g. '{')
* @param closingPeer
* the closing peer character (e.g. '}')
* @return the matching peer character position, or <code>NOT_FOUND</code>
*/
public int findOpeningPeer(int start, char openingPeer, char closingPeer) {
Assert.isLegal(start < fDocument.getLength());
try {
int depth = 1;
start += 1;
while (true) {
start = scanBackward(start - 1, UNBOUND, new CharacterMatch(
new char[] { openingPeer, closingPeer }));
if (start == NOT_FOUND)
return NOT_FOUND;
if (fDocument.getChar(start) == closingPeer)
depth++;
else
depth--;
if (depth == 0)
return start;
}
} catch (BadLocationException e) {
return NOT_FOUND;
}
}
/**
* Finds the smallest position in <code>fDocument</code> such that the
* position is >= <code>position</code> and < <code>bound</code> and
* <code>Character.isWhitespace(fDocument.getChar(pos))</code> evaluates to
* <code>false</code> and the position is in the default partition.
*
* @param position
* the first character position in <code>fDocument</code> to be
* considered
* @param bound
* the first position in <code>fDocument</code> to not consider
* any more, with <code>bound</code> > <code>position</code>,
* or <code>UNBOUND</code>
* @return the smallest position of a non-whitespace character in
* [<code>position</code>, <code>bound</code>) that resides in a Tcl
* partition, or <code>NOT_FOUND</code> if none can be found
*/
public int findNonWhitespaceForward(int position, int bound) {
return scanForward(position, bound, fNonWSDefaultPart);
}
/**
* Finds the smallest position in <code>fDocument</code> such that the
* position is >= <code>position</code> and < <code>bound</code> and
* <code>Character.isWhitespace(fDocument.getChar(pos))</code> evaluates to
* <code>false</code>.
*
* @param position
* the first character position in <code>fDocument</code> to be
* considered
* @param bound
* the first position in <code>fDocument</code> to not consider
* any more, with <code>bound</code> > <code>position</code>,
* or <code>UNBOUND</code>
* @return the smallest position of a non-whitespace character in
* [<code>position</code>, <code>bound</code>), or
* <code>NOT_FOUND</code> if none can be found
*/
public int findNonWhitespaceForwardInAnyPartition(int position, int bound) {
return scanForward(position, bound, fNonWS);
}
/**
* Finds the highest position in <code>fDocument</code> such that the
* position is <= <code>position</code> and > <code>bound</code> and
* <code>Character.isWhitespace(fDocument.getChar(pos))</code> evaluates to
* <code>false</code> and the position is in the default partition.
*
* @param position
* the first character position in <code>fDocument</code> to be
* considered
* @param bound
* the first position in <code>fDocument</code> to not consider
* any more, with <code>bound</code> < <code>position</code>,
* or <code>UNBOUND</code>
* @return the highest position of a non-whitespace character in
* (<code>bound</code>, <code>position</code>] that resides in a Tcl
* partition, or <code>NOT_FOUND</code> if none can be found
*/
public int findNonWhitespaceBackward(int position, int bound) {
return scanBackward(position, bound, fNonWSDefaultPart);
}
/**
* Finds the lowest position <code>p</code> in <code>fDocument</code> such
* that <code>start</code> <= p < <code>bound</code> and
* <code>condition.stop(fDocument.getChar(p), p)</code> evaluates to
* <code>true</code>.
*
* @param start
* the first character position in <code>fDocument</code> to be
* considered
* @param bound
* the first position in <code>fDocument</code> to not consider
* any more, with <code>bound</code> > <code>start</code>, or
* <code>UNBOUND</code>
* @param condition
* the <code>StopCondition</code> to check
* @return the lowest position in [<code>start</code>, <code>bound</code>)
* for which <code>condition</code> holds, or <code>NOT_FOUND</code>
* if none can be found
*/
public int scanForward(int start, int bound, StopCondition condition) {
Assert.isLegal(start >= 0);
if (bound == UNBOUND)
bound = fDocument.getLength();
Assert.isLegal(bound <= fDocument.getLength());
try {
fPos = start;
while (fPos < bound) {
fChar = fDocument.getChar(fPos);
if (condition.stop(fChar, fPos, true))
return fPos;
fPos = condition.nextPosition(fPos, true);
}
} catch (BadLocationException e) {
}
return NOT_FOUND;
}
/**
* Finds the lowest position in <code>fDocument</code> such that the
* position is >= <code>position</code> and < <code>bound</code> and
* <code>fDocument.getChar(position) == ch</code> evaluates to
* <code>true</code> and the position is in the default partition.
*
* @param position
* the first character position in <code>fDocument</code> to be
* considered
* @param bound
* the first position in <code>fDocument</code> to not consider
* any more, with <code>bound</code> > <code>position</code>,
* or <code>UNBOUND</code>
* @param ch
* the <code>char</code> to search for
* @return the lowest position of <code>ch</code> in (<code>bound</code>,
* <code>position</code>] that resides in a Tcl partition, or
* <code>NOT_FOUND</code> if none can be found
*/
public int scanForward(int position, int bound, char ch) {
return scanForward(position, bound, new CharacterMatch(ch));
}
/**
* Finds the lowest position in <code>fDocument</code> such that the
* position is >= <code>position</code> and < <code>bound</code> and
* <code>fDocument.getChar(position) == ch</code> evaluates to
* <code>true</code> for at least one ch in <code>chars</code> and the
* position is in the default partition.
*
* @param position
* the first character position in <code>fDocument</code> to be
* considered
* @param bound
* the first position in <code>fDocument</code> to not consider
* any more, with <code>bound</code> > <code>position</code>,
* or <code>UNBOUND</code>
* @param chars
* an array of <code>char</code> to search for
* @return the lowest position of a non-whitespace character in
* [<code>position</code>, <code>bound</code>) that resides in a Tcl
* partition, or <code>NOT_FOUND</code> if none can be found
*/
public int scanForward(int position, int bound, char[] chars) {
return scanForward(position, bound, new CharacterMatch(chars));
}
/**
* Finds the highest position <code>p</code> in <code>fDocument</code> such
* that <code>bound</code> < <code>p</code> <= <code>start</code> and
* <code>condition.stop(fDocument.getChar(p), p)</code> evaluates to
* <code>true</code>.
*
* @param start
* the first character position in <code>fDocument</code> to be
* considered
* @param bound
* the first position in <code>fDocument</code> to not consider
* any more, with <code>bound</code> < <code>start</code>, or
* <code>UNBOUND</code>
* @param condition
* the <code>StopCondition</code> to check
* @return the highest position in (<code>bound</code>, <code>start</code>
* for which <code>condition</code> holds, or <code>NOT_FOUND</code>
* if none can be found
*/
public int scanBackward(int start, int bound, StopCondition condition) {
if (bound == UNBOUND)
bound = -1;
Assert.isLegal(bound >= -1);
Assert.isLegal(start < fDocument.getLength());
try {
fPos = start;
while (fPos > bound) {
fChar = fDocument.getChar(fPos);
if (condition.stop(fChar, fPos, false))
return fPos;
fPos = condition.nextPosition(fPos, false);
}
} catch (BadLocationException e) {
}
return NOT_FOUND;
}
/**
* Finds the highest position in <code>fDocument</code> such that the
* position is <= <code>position</code> and > <code>bound</code> and
* <code>fDocument.getChar(position) == ch</code> evaluates to
* <code>true</code> for at least one ch in <code>chars</code> and the
* position is in the default partition.
*
* @param position
* the first character position in <code>fDocument</code> to be
* considered
* @param bound
* the first position in <code>fDocument</code> to not consider
* any more, with <code>bound</code> < <code>position</code>,
* or <code>UNBOUND</code>
* @param ch
* the <code>char</code> to search for
* @return the highest position of one element in <code>chars</code> in
* (<code>bound</code>, <code>position</code>] that resides in a Tcl
* partition, or <code>NOT_FOUND</code> if none can be found
*/
public int scanBackward(int position, int bound, char ch) {
return scanBackward(position, bound, new CharacterMatch(ch));
}
/**
* Finds the highest position in <code>fDocument</code> such that the
* position is <= <code>position</code> and > <code>bound</code> and
* <code>fDocument.getChar(position) == ch</code> evaluates to
* <code>true</code> for at least one ch in <code>chars</code> and the
* position is in the default partition.
*
* @param position
* the first character position in <code>fDocument</code> to be
* considered
* @param bound
* the first position in <code>fDocument</code> to not consider
* any more, with <code>bound</code> < <code>position</code>,
* or <code>UNBOUND</code>
* @param chars
* an array of <code>char</code> to search for
* @return the highest position of one element in <code>chars</code> in
* (<code>bound</code>, <code>position</code>] that resides in a Tcl
* partition, or <code>NOT_FOUND</code> if none can be found
*/
public int scanBackward(int position, int bound, char[] chars) {
return scanBackward(position, bound, new CharacterMatch(chars));
}
/**
* Checks whether <code>position</code> resides in a default (Tcl) partition
* of <code>fDocument</code>.
*
* @param position
* the position to be checked
* @return <code>true</code> if <code>position</code> is in the default
* partition of <code>fDocument</code>, <code>false</code> otherwise
*/
public boolean isDefaultPartition(int position) {
return fPartition.equals(getPartition(position).getType());
}
/**
* Returns the partition at <code>position</code>.
*
* @param position
* the position to get the partition for
* @return the partition at <code>position</code> or a dummy zero-length
* partition if accessing the document fails
*/
private ITypedRegion getPartition(int position) {
if (!contains(fCachedPartition, position)) {
Assert.isTrue(position >= 0);
Assert.isTrue(position <= fDocument.getLength());
try {
fCachedPartition = TextUtilities.getPartition(fDocument,
fPartitioning, position, false);
} catch (BadLocationException e) {
fCachedPartition = new TypedRegion(position, 0,
"__no_partition_at_all"); //$NON-NLS-1$
}
}
return fCachedPartition;
}
/**
* Returns <code>true</code> if <code>region</code> contains
* <code>position</code>.
*
* @param region
* a region
* @param position
* an offset
* @return <code>true</code> if <code>region</code> contains
* <code>position</code>
*
*/
private boolean contains(IRegion region, int position) {
int offset = region.getOffset();
return offset <= position && position < offset + region.getLength();
}
/**
* Computes the surrounding block around <code>offset</code>. The search is
* started at the beginning of <code>offset</code>, i.e. an opening brace at
* <code>offset</code> will not be part of the surrounding block, but a
* closing brace will.
*
* @param offset
* the offset for which the surrounding block is computed
* @return a region describing the surrounding block, or <code>null</code>
* if none can be found
*/
public IRegion findSurroundingBlock(int offset) {
if (offset < 1 || offset >= fDocument.getLength())
return null;
int begin = findOpeningPeer(offset - 1, '{', '}');
int end = findClosingPeer(offset, '{', '}');
if (begin == NOT_FOUND || end == NOT_FOUND)
return null;
return new Region(begin, end + 1 - begin);
}
}